Receiving random access response with extended response window

ABSTRACT

Method, apparatuses, and computer program product for addressing random access responses with extended response windows. One method may include accessing, by a user equipment, a network by sending a random access channel preamble to a network element. The method may also include receiving, in response to the random access channel preamble, a random access response from the network element. The random access response provides an indication of which random access channel occasion in time within a span of one or a plurality of radio frames the random access response applies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 17/043,403, filed Sep. 29, 2020 and entitled“Receiving Random Access Response with Extended Response Window,” whichis a National Phase Entry of International Patent Application No.PCT/CN2019/075123, filed Feb. 14, 2019 and entitled “Receiving RandomAccess Response with Extended Response Window,” the entire disclosuresof each of which are hereby incorporated herein by reference in theirentireties for all purposes.

FIELD

Some example embodiments may generally relate to mobile or wirelesstelecommunication systems, such as Long Term Evolution (LTE) or fifthgeneration (5G) radio access technology or new radio (NR) accesstechnology, or other communications systems. For example, certainembodiments may relate to apparatuses, systems, and/or methods foraddressing random access responses with extended response windows.

BACKGROUND

Examples of mobile or wireless telecommunication systems may include theUniversal Mobile Telecommunications System (UMTS) Terrestrial RadioAccess Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN(E-UTRAN), LTE-Advanced (LTE-A), MulteFire, LTE-A Pro, and/or fifthgeneration (5G) radio access technology or new radio (NR) accesstechnology. Fifth generation (5G) wireless systems refer to the nextgeneration (NG) of radio systems and network architecture. 5G is mostlybuilt on a new radio (NR), but the 5G (or NG) network can also build onE-UTRA radio. It is estimated that NR will provide bitrates on the orderof 10-20 Gbit/s or higher, and will support at least enhanced mobilebroadband (eMBB) and ultra-reliable low-latency-communication (URLLC) aswell as massive machine type communication (mMTC). NR is expected todeliver extreme broadband and ultra-robust, low latency connectivity andmassive networking to support the Internet of Things (IoT). With IoT andmachine-to-machine (M2M) communication becoming more widespread, therewill be a growing need for networks that meet the needs of lower power,low data rate, and long battery life. It is noted that, in 5G, the nodesthat can provide radio access functionality to a user equipment (i.e.,similar to Node B in UTRAN or eNB in LTE) may be named gNB when built onNR radio and may be named NG-eNB when built on E-UTRA radio.

SUMMARY

In accordance with some example embodiments, a method may includesending, by a user equipment, a random access channel preamble to anetwork element. The method may also include receiving, in response tosending the random access channel preamble, a random access responsefrom the network element. In an example embodiment, the random accessresponse may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

In accordance with some example embodiments, an apparatus may includemeans for sending a random access channel preamble to a network element.The apparatus may also include means for receiving, in response tosending the random access channel preamble, a random access responsefrom the network element. In an example embodiment, the random accessresponse may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

In accordance with some example embodiments, an apparatus may include atleast one processor and at least one memory including computer programcode. The at least one memory and the computer program code may beconfigured to, with the at least one processor, cause the apparatus atleast to send a random access channel preamble to a network element. Theat least one memory and the computer program code may also be configuredto, with the at least one processor, cause the apparatus at least toreceive, in response to sending the random access channel preamble, arandom access response from the network element. In an exampleembodiment, the random access response may provide an indication ofwhich random access channel occasion in time within a span of one or aplurality of radio frames the random access response applies.

In accordance with some example embodiments, a non-transitory computerreadable medium can be encoded with instructions that may, when executedin hardware, perform a method. The method may sending a random accesschannel preamble to a network element. The method may also receive, inresponse to sending the random access channel preamble, a random accessresponse from the network element. In an example embodiment, the randomaccess response may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

In accordance with some example embodiments, a computer program productmay perform a method. The method may send a random access channelpreamble to a network element. The method may also receive, in responseto sending the random access channel preamble, a random access responsefrom the network element. In an example embodiment, the random accessresponse may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

In accordance with some example embodiments, an apparatus may includecircuitry configured to send a random access channel preamble to anetwork element. The apparatus may also include circuitry configured toreceive, in response to sending the random access channel preamble, arandom access response from the network element. In an exampleembodiment, the random access response may provide an indication ofwhich random access channel occasion in time within a span of one or aplurality of radio frames the random access response applies

In accordance with some example embodiments, a method may includereceiving, at a network element, a random access channel preamble from auser equipment. The method may also include sending, in response to therandom access channel preamble, a random access response to the userequipment. In an example embodiment, the random access response mayprovide an indication of which random access channel occasion in timewithin a span of one or a plurality of radio frames the random accessresponse applies.

In accordance with some example embodiments, an apparatus may includemeans for receiving, at a network element, a random access channelpreamble from a user equipment. The apparatus may also include means forsending, in response to the random access channel preamble, a randomaccess response to the user equipment. In an example embodiment, therandom access response may provide an indication of which random accesschannel occasion in time within a span of one or a plurality of radioframes the random access response applies.

In accordance with some example embodiments, an apparatus may include atleast one processor and at least one memory including computer programcode. The at least one memory and the computer program code may beconfigured to, with the at least one processor, cause the apparatus atleast to receive a random access channel preamble from a user equipment.The at least one memory and the computer program code may also beconfigured to, with the at least one processor, cause the apparatus atleast to send, in response to the random access channel preamble, arandom access response to the user equipment. In an example embodiment,the random access response may provide an indication of which randomaccess channel occasion in time within a span of one or a plurality ofradio frames the random access response applies.

In accordance with some example embodiments, a non-transitory computerreadable medium can be encoded with instructions that may, when executedin hardware, perform a method. The method may receive, at a networkelement, a random access channel preamble from a user equipment. Themethod may also send, in response to the random access channel preamble,a random access response to the user equipment. In an exampleembodiment, the random access response may provide an indication ofwhich random access channel occasion in time within a span of one or aplurality of radio frames the random access response applies.

In accordance with some example embodiments, a computer program productmay perform a method. The method may receive, at a network element, arandom access channel preamble from a user equipment. The method mayalso send, in response to the random access channel preamble, a randomaccess response to the user equipment. In an example embodiment, therandom access response may provide an indication of which random accesschannel occasion in time within a span of one or a plurality of radioframes the random access response applies.

In accordance with some embodiments, an apparatus may include circuitryconfigured to receive a random access channel preamble from a userequipment. The apparatus may also include circuitry configured to send,in response to the random access channel preamble, a random accessresponse to the user equipment. In an example embodiment, the randomaccess response may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

BRIEF DESCRIPTION OF THE DRAWINGS

For proper understanding of the invention, reference should be made tothe accompanying drawings, wherein:

FIG. 1 illustrates an example 2-step random access channel (RACH) signalflow.

FIG. 2 illustrates possible response timings, according to an exampleembodiment.

FIG. 3 illustrates an example flow diagram of a method, according to anembodiment.

FIG. 4 illustrates an example flow diagram of another method accordingto an example embodiment.

FIG. 5 a illustrates a block diagram of an apparatus according to anexample embodiment

FIG. 5 b illustrates a block diagram of another apparatus according toan example embodiment.

DETAILED DESCRIPTION

It will be readily understood that the components of certain exampleembodiments, as generally described and illustrated in the figuresherein, may be arranged and designed in a wide variety of differentconfigurations. Thus, the following detailed description of some exampleembodiments of systems, methods, apparatuses, and computer programproducts for addressing random access responses with extended responsewindow, is not intended to limit the scope of certain embodiments but isrepresentative of selected example embodiments.

The features, structures, or characteristics of example embodimentsdescribed throughout this specification may be combined in any suitablemanner in one or more example embodiments. For example, the usage of thephrases “certain embodiments,” “an example embodiment,” “someembodiments,” or other similar language, throughout this specificationrefers to the fact that a particular feature, structure, orcharacteristic described in connection with an embodiment may beincluded in at least one embodiment. Thus, appearances of the phrases“in certain embodiments,” “an example embodiment,” “in someembodiments,” “in other embodiments,” or other similar language,throughout this specification do not necessarily all refer to the samegroup of embodiments, and the described features, structures, orcharacteristics may be combined in any suitable manner in one or moreexample embodiments.

Additionally, if desired, the different functions or steps discussedbelow may be performed in a different order and/or concurrently witheach other. Furthermore, if desired, one or more of the describedfunctions or steps may be optional or may be combined. As such, thefollowing description should be considered as merely illustrative of theprinciples and teachings of certain example embodiments, and not inlimitation thereof.

Certain example embodiments may relate to random access (RA) proceduresfor 3GPP New Radio (NR) design. Other example embodiments may relate torandom access response (RAR) reception for NR radio operating in anunlicensed spectrum or MsgB reception for a 2-step random access (RA)procedure.

Certain proposals have been made in 3GPP having a work item on NR-basedaccess to an unlicensed spectrum, as well as on 2-step random accesschannel (RACH) for NR. For example, for an RA procedure, RA may specifyrequired NR modifications to enhance RACH procedure in line with theagreements during the study phase, including 4-step RACH modificationsto handle reduced Msg 1/2/3/4 transmission opportunities due to listenbefore talk (LBT) failure (radio access network (RAN) 1/RAN2. Further,for RA procedure, LBT for 2-step RACH and application of physical randomaccess channel (PRACH) and physical uplink shared channel (PUSCH) formatimprovements for NR-U to 2-step RACH may be provided.

For Msg2 in an initial access and mobility, TR 38.889 describes that insome scenarios for Msg2 transmission in the 4-step RACH, it may bebeneficial for the maximum RAR window size to be extended beyond 10 msto improve robustness to downlink (DL) LBT failure for an RARtransmission Thus, an ra-ResponseWindow may be extended over 10 ms toimprove the robustness for RAR transmissions against DL LBT failuresblocking the intended transmission.

FIG. 1 illustrates an example 2-step RACH signal flow. In view of the2-step RACH signal flow in FIG. 1 , some outcomes of the 2-step RACHhave been captured in the technical report (TR) for the NR-U SI. Forexample, for 2-step RACH, the msgA may be a signal to detect the userequipment (UE) and a payload while the second message may be forcontention resolution for contention based random access (CBRA) with apossible payload. MsgA may at least include the equivalent informationwhich is transmitted in msg3 for 4-step RACH. In addition, further inputfrom RAN1 may be needed for the payload size of msgA.

With the above in mind, as a baseline, all triggers for 4-step RACH maybe applicable to 2-step RACH. However, further analysis is needed on asignal information (SI) request and beam failure recovery (BFR), as wellas how timing advance and grants may be obtained for msgA. In addition,the contention resolution in the 2-step RACH may be performed byincluding a UE identifier in the first message which is echoed in thesecond message. Further, fallback from 2-step RACH to 4-step RACH may besupported. For instance, the fallback after msgA transmission may befeasible only if detection of the UE without the decoding of the payloadis possible and, thus, relies on such support at the physical layer. If,however, 2-step RACH is used for the initial access, the parameters for2-step RACH procedure including resources for msgA may be broadcasted.

The 2-step RACH procedure may include several objectives. One object mayspecify msgA's content to include the equivalent contents of msg3 of4-step RACH (RAN2/RAN1) Here, the inclusion of uplink controlinformation (UCI) in msgA is not precluded. Another objective mayspecify MsgB's content to include the equivalent contents of msg2 andmsg4 of 4 step-RACH (RAN1/RAN2). Further objectives may specifycontention resolution for 2-step RACH (RAN2), and specify a design of aradio network temporary identifier (RNTI) for MsgB of 2-step RACH(RAN2). In yet another objective, the fallback procedure may bespecified from 2-step RACH to 4-step RACH (RAN2/RAN1), and all triggersfor Rel-15 NR 4-step RACH may be applied for 2-step RACH except for SIrequest for BFR, which are up to RAN2 discussion In all the triggers froRel-15 NR 4-step RACH, there are no new triggers from 2-step RACH.

For contention resolution in 2-step RACH, the response may be within thecontention resolution timer as in 4-step RACH to leave the network (NW)enough time to process the radio resource control (RRC) message(s). Incontention resolution, values of the contention resolution timer(ra-ContentionResolutionTimer) in NR Rel-15 may include: sf8; sf16;sf24; sf32; sf40, sf48, sf56; and sf64. The initial value for thecontention resolution timer, sf8, corresponds to 8 subframes, and thevalue sf16 corresponds to 16 subframes, and so on.

With the subframe always being 1 ms in NR, the maximum value for thetimer is therefore 64 ms. Further, random access radio network temporaryidentifier (RA-RNTI) in NR Rel-15 (TS 38.321) associated with RApreamble transmission is based on the following formula (1).

RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id  (1)

The RA-RNTI associated with the PRACH/RACH occasion in which the RApreamble is transmitted is computed according to the above formula (1).In formula (1), s_id is the index of the first orthogonal frequencydivision multiplexing (OFDM) symbol of the specified PRACH (0≤s_id<14),t_id is the index of the first slot of the specified PRACH in a systemframe (0≤t_id<80), f_id is the index of the specified PRACH in thefrequency domain (0≤f_id<8), and ul_carrier_id is the uplink (UL)carrier used for Msg1 transmission (0 for normal uplink (NUL) carrier,and 1 for supplementary uplink (SUL) carrier). Hence, the RA-RNTI may beunique only within the span of one radio frame/system frame/system framenumber duration, i.e., 10 ms.

In response to a PRACH preamble transmission, a UE may attempt to detecta DCI format 1_0 with cyclic redundancy check (CRC) scrambled by acorresponding RA-RNTI during a RAR window. If the UE detects the DCIformat 1_0 with CRC scrambled by the corresponding RA-RNTI and atransport block in a corresponding physical downlink shared channel(PDSCH) within the window, the UE may pass the transport block to higherlayers. The higher layers may then parse the transport block from arandom access preamble identity (RAPID) associated with the PRACHtransmission. If the higher layers identify the RAPID in RAR message(s)of the transport block, the higher layers may indicate an UL grant tothe physical layer. Such an indication may be referred to as a randomaccess response (RAR) UL grant.

The DCI for scheduling RAR with RA-RNTI in NR Rel-15 may be defined byinformation transmitted by means of the DCI format 1_0 with CRCscrambled by RA-RNTI. One such information may include frequency domainresource assignment with

$\left\lbrack {\log_{2}\left( {N_{RB}^{{DL},{BWP}}\frac{\left( {N_{RB}^{{DL},{BWP}} + 1} \right)}{2}} \right)} \right\rbrack{{bits}.}$

Here, N_(RB) ^(DLBWP) is the size of CORESET 0 if CORESET 0 isconfigured for the cell, and N_(RB) ^(DLBWP) is the size of the initialDL bandwidth part if CORESET 0 is not configured with the cell. Further,the time domain resource assignment may be transmitted, which mayinclude 4 bits. In addition, virtual resource block-to-physical resourceblock (VRB-to-PRB) mapping may be transmitted with 1 bit, the modulationand coding scheme may be transmitted with 5 bits, the TB scaling may betransmitted with 2 bits, and reserved bits may include 16 bits.

The contents of the RAR UL grant, starting with the most significant bit(MSB) and ending with the least significant bit (LSB), may be given inthe following table:

TABLE 1 Contents of the RAR UL Grant RAR grant field Number of bitsFrequency hopping flag 1 PUSCH frequency resource allocation 14 PUSCHtime resource allocation 4 MCS 4 TPC command for PUSCH 3 CSI request 1

From the above, it can be seen that in the RA-RNTI calculation formula,it is unique only within a duration of system/radio frame that is 10 msin NR. This means that any RO (RACH occasion) happening at the sametime/f_id in subsequent radio frames will have the same RA-RNTI derivedby the UEs and used for RAR reception.

However, current formula results already to a maximum of about 18,000RA-RNTI values (RNTI space being 64 k). Thus, it may be difficult toextend the formula to make ROs in subsequent radio frames unique interms of RA-RNTI. Specifically, if considering the 2-step MsgB addressedto RA-RNTI with contention resolution timer being, for example, 40 ms,this would already exhaust the RNTI space complete, which is notpossible for the system to work. Thus, at most, the RA-RNTI formula maybe extended to cover, for example, more frequency domain PRACHallocation than currently available (e.g., 8 PRACH allocations), whichwould increase the required space more moderately on the other hand,this would also bring issues. However, doing so would not solve theissue with a response window length over 10 ms. Thus, it may bedesirable to have an RA-RNTI calculation formula that would not need tobe revised to extend over radio frame borders.

According to certain example embodiments, when ra-Response Window forreceiving RAR or ra-ContentionResolutionTimer (or any other timerdefined for the purpose) for receiving MsgB is configured to be greaterthan 10 ms, the NW may indicate in the response for which RO in timewithin a span of one or multiple radio frames, the response applieswithout extending the RA-RNTI space. In other words, the response mayindicate which RO the response applies without extending the RA-RNTIspace since different ROs may hence use the same RA-RNTI for schedulingthe response In certain example embodiments, the response may be DCI orRAR/MsgB.

FIG. 2 illustrates possible response timings according to an exampleembodiment. For example, FIG. 2 illustrates possible response timingswhich need to indicate to which RO the response applies. As illustratedin FIG. 2 , the RAR with RA-RNTI pointing to RO #0 indicates whether itis for system frame number (SFN) #0, #1, or #2 RO.

According to certain example embodiments, the indication about the ROthe response applies may be provided via various mechanisms. Forexample, in one example embodiment, the indication about the RO theresponse applies may be provided in the DCI scheduling the RAR/MsgB Thismay utilize the existing reserved bits available in the DCI format Inanother example embodiment, the indication about the RO the responseapplies may be provided in the RAR/MsgB message itself and/or themessage could consist of multiple indications about multiple ROs. Thebenefit of this option against providing the indication in the DCIscheduling the RAR/MsgB is that multiple ROs may be responded within asingle RAR/MsgB. However, the drawback may be that the UE may have todecode the medium access control (MAC) protocol data unit (PDU) beforebeing able to determine whether the response message corresponds to theRO where it transmitted the preamble. In a further example embodiment,the NW may configure which one of the above mechanisms are used.

In certain example embodiments, the indication in the response providedby the NW may include various contents. For example, in one exampleembodiment, the indication may include the LSBs of SFN preceding theresponse message scheduling, or the LSBs of SFN of PRACH resource/RACHoccasion (RO) where the preamble was transmitted. For instance, 3 LSBsmay allow ROs within 8 radio frames (i.e., 80 ms) to be indicated withthe same RA-RNTI. This would also cover the maximumra-ContentionResolutionTimer value defined in Rel-15.

In another example embodiment, the indication may be just an indexoffset in radio frames from the radio frame where the response messageis scheduled. For instance, an index offset #0 means the current radioframe (i.e., the same radio frame where the response message isscheduled), #1 means the previous radio frame, and so on. Further, thenetwork may configure whether the UE should decode for the indication oralternatively, the UE may determine this based on the ra-Response Windowand/or ra-ContentionResolutionTimer lengths configured (i.e., ifconfigured to be greater than 10 ms).

Additionally or alternatively, in another example embodiment, the sameRA-RNTI may also be applied in the frequency domain if at a certainpoint in time, there are more than 8 ROs in the frequency. Here, the DCIscheduling the response message or the response message itself mayindicate for which RO in frequency the response applies. This indicationmay be additional or alternative to the time domain indication.

According to certain example embodiments, the indication may include aone bit indication, which may allow 16 ROs/PRACHs in frequency. This maybe done since setting the bit would mean the ROs 8-15 in frequencydomain and the actual index in between may be obtained by taking intoaccount the actual f_id used in the RA-RNTI formula. For instance,setting the bit means f_id===8+f_id.

FIG. 3 illustrates an example flow diagram of a method according to anexample embodiment. In certain example embodiments, the flow diagram ofFIG. 3 may be performed by a mobile station and/or UE, for instance.According to one embodiment, the method of FIG. 3 may include initially,at 300, accessing a network by sending a random access channel preambleto a network element. The method may also include, at 305, receiving, inresponse to the random access channel preamble, a random access responsefrom the network element In an example embodiment, the random accessresponse may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

FIG. 4 illustrates an example flow diagram of another method accordingto an example embodiment. In certain example embodiments, the flowdiagram of FIG. 4 may be performed by a network entity or network nodein a 3GPP system, such as LTE or 5G NR. For instance, in some exampleembodiments, the method of FIG. 4 may be performed by a base station,eNB, or gNB.

According to one example embodiment, the method of FIG. 4 may includeinitially, at 400, receiving a random access channel preamble from auser equipment. The method may also include, at 405, sending, inresponse to the random access channel preamble, a random access responseto the user equipment. According to an example embodiment, the randomaccess response may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

In an example embodiment, a window for receiving the random accessresponse may be greater than 10 ms. In another example embodiment, theindication may be provided in a downlink control information schedulingthe random access response. In a further example embodiment, theindication may be provided in the random access response itself, and therandom access response may include a plurality of indications about aplurality of random access channel occasions. According to anotherexample embodiment, the indication may include a plurality of leastsignificant bits of a system frame number preceding a random accessresponse scheduling, or a plurality of least significant bits of aplurality of a system frame number of a physical random access channelresource. In another example embodiment, the indication may include anindex offset in radio frames from a radio frame where the random accessresponse is scheduled. According to a further example embodiment, a samerandom access radio network temporary identifier may be applied in afrequency domain when there are more than 8 random access channeloccasions in frequency.

FIG. 5 a illustrates an example of an apparatus 10 according to anotherembodiment In an embodiment, apparatus 10 may be a node or element in acommunications network or associated with such a network, such as a UE,mobile equipment (ME), mobile station, mobile device, stationary device,IoT device, or other device. As described herein, UE may alternativelybe referred to as, for example, a mobile station, mobile equipment,mobile unit, mobile device, user device, subscriber station, wirelessterminal, tablet, smart phone, IoT device, sensor or NB-IoT device, orthe like. As one example, apparatus 10 may be implemented in, forinstance, a wireless handheld device, a wireless plug-in accessory, orthe like.

In some example embodiments, apparatus 10 may include one or moreprocessors, one or more computer-readable storage medium (for example,memory, storage, or the like), one or more radio access components (forexample, a modem, a transceiver, or the like), and/or a user interface.In some embodiments, apparatus 10 may be configured to operate using oneor more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G,WLAN, WiFi, NB-IoT, Bluetooth, NFC, MulteFire, and/or any other radioaccess technologies. It should be noted that one of ordinary skill inthe art would understand that apparatus 10 may include components orfeatures not shown in FIG. 5 a.

As illustrated in the example of FIG. 5 a , apparatus 10 may include orbe coupled to a processor 12 for processing information and executinginstructions or operations. Processor 12 may be any type of general orspecific purpose processor. In fact, processor 12 may include one ormore of general-purpose computers, special purpose computers,microprocessors, digital signal processors (DSPs), field-programmablegate arrays (FPGAs), application-specific integrated circuits (ASICs),and processors based on a multi-core processor architecture, asexamples. While a single processor 12 is shown in FIG. 5 a , multipleprocessors may be utilized according to other embodiments. For example,it should be understood that, in certain example embodiments, apparatus10 may include two or more processors that may form a multiprocessorsystem (e.g., in this case processor 12 may represent a multiprocessor)that may support multiprocessing. According to certain exampleembodiments, the multiprocessor system may be tightly coupled or looselycoupled (e.g., to form a computer cluster).

Processor 12 may perform functions associated with the operation ofapparatus 10 including, as some examples, precoding of antennagain/phase parameters, encoding and decoding of individual bits forminga communication message, formatting of information, and overall controlof the apparatus 10, including processes related to management ofcommunication resources.

Apparatus 10 may further include or be coupled to a memory 14 (internalor external), which may be coupled to processor 12, for storinginformation and instructions that may be executed by processor 12.Memory 14 may be one or more memories and of any type suitable to thelocal application environment, and may be implemented using any suitablevolatile or nonvolatile data storage technology such as asemiconductor-based memory device, a magnetic memory device and system,an optical memory device and system, fixed memory, and/or removablememory. For example, memory 14 can be comprised of any combination ofrandom access memory (RAM), read only memory (ROM), static storage suchas a magnetic or optical disk, hard disk drive (HDD), or any other typeof non-transitory machine or computer readable media. The instructionsstored in memory 14 may include program instructions or computer programcode that, when executed by processor 12, enable the apparatus 10 toperform tasks as described herein.

In an embodiment, apparatus 10 may further include or be coupled to(internal or external) a drive or port that is configured to accept andread an external computer readable storage medium, such as an opticaldisc, USB drive, flash drive, or any other storage medium. For example,the external computer readable storage medium may store a computerprogram or software for execution by processor 12 and/or apparatus 10.

In some embodiments, apparatus 10 may also include or be coupled to oneor more antennas 18 for receiving a downlink signal and for transmittingvia an uplink from apparatus 10. Apparatus 10 may further include atransceiver 18 configured to transmit and receive information. Thetransceiver 28 may also include a radio interface (e.g., a modem)coupled to the antenna 15. The radio interface may correspond to aplurality of radio access technologies including one or more of GSM,LTE, LTE-A, 5G, NR, WLAN, NB-IoT, Bluetooth, BT-LE, NFC, RFID, UWB, andthe like. The radio interface may include other components, such asfilters, converters (for example, digital-to-analog converters and thelike), symbol demappers, signal shaping components, an Inverse FastFourier Transform (IFFT) module, and the like, to process symbols, suchas OFDMA symbols, carried by a downlink or an uplink.

For instance, transceiver 18 may be configured to modulate informationon to a carrier waveform for transmission by the antenna(s) 15 anddemodulate information received via the antenna(s) 15 for furtherprocessing by other elements of apparatus 10. In other embodiments,transceiver 18 may be capable of transmitting and receiving signals ordata directly Additionally or alternatively, in some embodiments,apparatus 10 may include an input and/or output device (I/O device). Incertain embodiments, apparatus 10 may further include a user interface,such as a graphical user interface or touchscreen.

In an embodiment, memory 14 stores software modules that providefunctionality when executed by processor 12. The modules may include,for example, an operating system that provides operating systemfunctionality for apparatus 10. The memory may also store one or morefunctional modules, such as an application or program, to provideadditional functionality for apparatus 10. The components of apparatus10 may be implemented in hardware, or as any suitable combination ofhardware and software. According to an example embodiment, apparatus 10may optionally be configured to communicate with apparatus 20 via awireless or wired communications link 70 according to any radio accesstechnology, such as NR.

According to certain example embodiments, processor 12 and memory 14 maybe included in or may form a part of processing circuitry or controlcircuitry. In addition, in some embodiments, transceiver 28 may beincluded in or may form a part of transceiving circuitry.

As discussed above, according to certain example embodiments, apparatus10 may be a UE, mobile device, mobile station, ME, IoT device and/orNB-IoT device, for example. According to certain embodiments, apparatus10 may be controlled by memory 14 and processor 12 to perform thefunctions associated with example embodiments described herein. Forexample, in some embodiments, apparatus 10 may be configured to performone or more of the processes depicted in any of the flow charts orsignaling diagrams described herein, such as the flow diagramsillustrated in FIGS. 1, 2, and 3 .

For instance, in one embodiment, apparatus 10 may be controlled bymemory 14 and processor 12 to access a network by sending a randomaccess channel preamble to a network element. The apparatus 10 may alsobe controlled by memory 14 and processor 12 to receive, in response tosending the random access channel preamble, a random access responsefrom the network element. In an example embodiment, the random accessresponse may provide an indication of which random access channeloccasion in time within a span of one or a plurality of radio frames therandom access response applies.

FIG. 5 b illustrates an example of an apparatus 20 according to anexample embodiment. In an example embodiment, apparatus 20 may be anode, host, or server in a communication network or serving such anetwork. For example, apparatus 20 may be a satellite, base station, aNode B, an evolved Node B (eNB), 5G Node B or access point, nextgeneration Node B (NG-NB or gNB), and/or WLAN access point, associatedwith a radio access network (RAN), such as an LTE network, 5G or NR Incertain example embodiments, apparatus 20 may be an eNB in LTE or gNB in5G.

It should be understood that, in some example embodiments, apparatus 20may be comprised of an edge cloud server as a distributed computingsystem where the server and the radio node may be stand-aloneapparatuses communicating with each other via a radio path or via awired connection, or they may be located in a same entity communicatingvia a wired connection. For instance, in certain example embodimentswhere apparatus 20 represents a gNB, it may be configured in a centralunit (CU) and distributed unit (DU) architecture that divides the gNBfunctionality. In such an architecture, the CU may be a logical nodethat includes gNB functions such as transfer of user data, mobilitycontrol, radio access network sharing, positioning, and/or sessionmanagement, etc. The CU may control the operation of DU(s) over afront-haul interface. The DU may be a logical node that includes asubset of the gNB functions, depending on the functional split option.It should be noted that one of ordinary skill in the art wouldunderstand that apparatus 20 may include components or features notshown in FIG. 5 b.

As illustrated in the example of FIG. 5 b , apparatus 20 may include aprocessor 22 for processing information and executing instructions oroperations. Processor 22 may be any type of general or specific purposeprocessor For example, processor 22 may include one or more ofgeneral-purpose computers, special purpose computers, microprocessors,digital signal processors (DSPs), field-programmable gate arrays(FPGAs), application-specific integrated circuits (ASICs), andprocessors based on a multi-core processor architecture, as examples.While a single processor 22 is shown in FIG. 5 b , multiple processorsmay be utilized according to other embodiments. For example, it shouldbe understood that, in certain embodiments, apparatus 20 may include twoor more processors that may form a multiprocessor system (e.g., in thiscase processor 22 may represent a multiprocessor) that may supportmultiprocessing In certain embodiments, the multiprocessor system may betightly coupled or loosely coupled (e.g., to form a computer cluster).

According to certain example embodiments, processor 22 may performfunctions associated with the operation of apparatus 20, which mayinclude, for example, precoding of antenna gain/phase parameters,encoding and decoding of individual bits forming a communicationmessage, formatting of information, and overall control of the apparatus20, including processes related to management of communicationresources.

Apparatus 20 may further include or be coupled to a memory 24 (internalor external), which may be coupled to processor 22, for storinginformation and instructions that may be executed by processor 22.Memory 24 may be one or more memories and of any type suitable to thelocal application environment, and may be implemented using any suitablevolatile or nonvolatile data storage technology such as asemiconductor-based memory device, a magnetic memory device and system,an optical memory device and system, fixed memory, and/or removablememory. For example, memory 24 can be comprised of any combination ofrandom access memory (RAM), read only memory (ROM), static storage suchas a magnetic or optical disk, hard disk drive (1-DD), or any other typeof non-transitory machine or computer readable media. The instructionsstored in memory 24 may include program instructions or computer programcode that, when executed by processor 22, enable the apparatus 20 toperform tasks as described herein.

In an embodiment, apparatus 20 may further include or be coupled to(internal or external) a drive or port that is configured to accept andread an external computer readable storage medium, such as an opticaldisc, USB drive, flash drive, or any other storage medium. For example,the external computer readable storage medium may store a computerprogram or software for execution by processor 22 and/or apparatus 20.

In certain example embodiments, apparatus 20 may also include or becoupled to one or more antennas 25 for transmitting and receivingsignals and/or data to and from apparatus 20 Apparatus 20 may furtherinclude or be coupled to a transceiver 28 configured to transmit andreceive information. The transceiver 28 may include, for example, aplurality of radio interfaces that may be coupled to the antenna(s) 25.The radio interfaces may correspond to a plurality of radio accesstechnologies including one or more of GSM, NB-IoT, LTE, 5G, WLAN,Bluetooth, BT-LE, NFC, radio frequency identifier (RFID), ultrawideband(UWB), MulteFire, and the like. The radio interface may includecomponents, such as filters, converters (for example, digital-to-analogconverters and the like), mappers, a Fast Fourier Transform (FFT)module, and the like, to generate symbols for a transmission via one ormore downlinks and to receive symbols (for example, via an uplink).

As such, transceiver 28 may be configured to modulate information on toa carrier waveform for transmission by the antenna(s) 25 and demodulateinformation received via the antenna(s) 25 for further processing byother elements of apparatus 20. In other embodiments, transceiver 18 maybe capable of transmitting and receiving signals or data directly.Additionally or alternatively, in some embodiments, apparatus 20 mayinclude an input and/or output device (I/O device).

In an embodiment, memory 24 may store software modules that providefunctionality when executed by processor 22. The modules may include,for example, an operating system that provides operating systemfunctionality for apparatus 20. The memory may also store one or morefunctional modules, such as an application or program, to provideadditional functionality for apparatus 20. The components of apparatus20 may be implemented in hardware, or as any suitable combination ofhardware and software.

According to some embodiments, processor 22 and memory 24 may beincluded in or may form a part of processing circuitry or controlcircuitry. In addition, in some embodiments, transceiver 28 may beincluded in or may form a part of transceiving circuitry.

As used herein, the term “circuitry” may refer to hardware-onlycircuitry implementations (e.g., analog and/or digital circuitry),combinations of hardware circuits and software, combinations of analogand/or digital hardware circuits with software/firmware, any portions ofhardware processor(s) with software (including digital signalprocessors) that work together to case an apparatus (e.g., apparatus 20)to perform various functions, and/or hardware circuit(s) and/orprocessor(s), or portions thereof, that use software for operation butwhere the software may not be present when it is not needed foroperation. As a further example, as used herein, the term “circuitry”may also cover an implementation of merely a hardware circuit orprocessor (or multiple processors), or portion of a hardware circuit orprocessor, and its accompanying software and/or firmware. The termcircuitry may also cover, for example, a baseband integrated circuit ina server, cellular network node or device, or other computing or networkdevice.

As introduced above, in certain embodiments, apparatus 20 may be anetwork node or RAN node, such as a base station, access point, Node B,eNB, gNB, WLAN access point, or the like. According to certainembodiments, apparatus 10 may be controlled by memory 24 and processor22 to perform the functions associated with any of the embodimentsdescribed herein, such as the flow or signaling diagrams illustrated inFIGS. 1, 2, and 4 .

For instance, in one embodiment, apparatus 20 may be controlled bymemory 24 and processor 22 to receiving a random access channel preamblefrom a user equipment to access a network. The apparatus 20 may also becontrolled by memory 24 and processor 22 to send, in response to therandom access channel preamble, a random access response to the userequipment In an example embodiment, the random access response mayprovide an indication of which random access channel occasion in timewithin a span of one or a plurality of radio frames the random accessresponse applies.

Certain example embodiments described herein provide several technicalimprovements, enhancements, and/or advantages. For example, according tocertain example embodiments, the RA-RNTI formula as defined in Rel-15 NRmay be applied as is. Alternatively, the RA-RNTI formula as defined inRel-15 NR may at least not need to be extended in the time domain, whichcan save unnecessary RA-RNTI allocations drastically when extending theRA response window length or introducing a long contention resolutionwindow for MsgB.

In some example embodiments, the functionality of any of the methods,processes, signaling diagrams, algorithms or flow charts describedherein may be implemented by software and/or computer program code orportions of code stored in memory or other computer readable or tangiblemedia, and executed by a processor.

In some example embodiments, an apparatus may be included or beassociated with at least one software application, module, unit orentity configured as arithmetic operation(s), or as a program orportions of it (including an added or updated software routine),executed by at least one operation processor. Programs, also calledprogram products or computer programs, including software routines,applets and macros, may be stored in any apparatus-readable data storagemedium and include program instructions to perform particular tasks.

A computer program product may comprise one or more computer-executablecomponents which, when the program is run, are configured to carry outsome example embodiments. The one or more computer-executable componentsmay be at least one software code or portions of it. Modifications andconfigurations required for implementing functionality of an exampleembodiment may be performed as routine(s), which may be implemented asadded or updated software routine(s). Software routine(s) may bedownloaded into the apparatus.

As an example, software or a computer program code or portions of it maybe in a source code form, object code form, or in some intermediateform, and it may be stored in some sort of carrier, distribution medium,or computer readable medium, which may be any entity or device capableof carrying the program. Such carriers may include a record medium,computer memory, read-only memory, photoelectrical and/or electricalcarrier signal, telecommunications signal, and software distributionpackage, for example. Depending on the processing power needed, thecomputer program may be executed in a single electronic digital computeror it may be distributed amongst a number of computers. The computerreadable medium or computer readable storage medium may be anon-transitory medium.

In other example embodiments, the functionality may be performed byhardware or circuitry included in an apparatus (e.g., apparatus 10 orapparatus 20), for example through the use of an application specificintegrated circuit (ASIC), a programmable gate array (PGA), a fieldprogrammable gate array (FPGA), or any other combination of hardware andsoftware. In yet another example embodiment, the functionality may beimplemented as a signal, a non-tangible means that can be carried by anelectromagnetic signal downloaded from the Internet or other network.

According to an example embodiment, an apparatus, such as a node,device, or a corresponding component, may be configured as circuitry, acomputer or a microprocessor, such as single-chip computer element, oras a chipset, including at least a memory for providing storage capacityused for arithmetic operation and an operation processor for executingthe arithmetic operation.

One having ordinary skill in the art will readily understand that theinvention as discussed above may be practiced with steps in a differentorder, and/or with hardware elements in configurations which aredifferent than those which are disclosed. Therefore, although theinvention has been described based upon these preferred embodiments, itwould be apparent to those of skill in the art that certainmodifications, variations, and alternative constructions would beapparent, while remaining within the spirit and scope of the invention.Although the above embodiments refer to 5G NR and LTE technology, theabove embodiments may also apply to any other present or future 3GPPtechnology, such as LTE-advanced, and/or fourth generation (4G)technology.

Partial Glossary DCI Downlink Control Information eNB Enhanced Node B(LTE base station) gNB 5G or NR Base Station LBT Listen Before Talk LSBLeast Significant Bits LTE Long Term Evolution MU Multi-User NW NetworkNR New Radio NR-U New Radio Unlicensed PRACH Physical Random AccessChannel PRB Physical Resource Block RA Random Access RACH Random AccessChannel RAR Random Access Response RNTI Radio Network TemporaryIdentifier RO RACH Occasion SFN System Frame Number UE User Equipment ULUplink

1. An apparatus comprising: at least one processor; and at least onememory storing program codes, wherein the at least one memory and theprogram codes are configured, with the at least one processor, to causethe apparatus at least to: send, to a network element, a transmissioncomprising a random access channel preamble; receive, in response tosending the transmission comprising the random access preamble, from thenetwork element, downlink control information for scheduling a randomaccess response associated with the transmission; and determine, basedat least on a length of a window for receiving the random accessresponse, to decode for an indication in the downlink controlinformation, wherein the indication indicates a random access channeloccasion in time within a span of one or a plurality of radio frames towhich the random access response applies, and wherein the indicationcomprises a plurality of least significant bits of a system frame numbercorresponding to the random access channel occasion.
 2. The apparatusaccording to claim 1, wherein the random access response is comprised inan msg2 in a four-step random access procedure, or comprised in an MsgBin a two-step random access procedure.
 3. The apparatus according toclaim 1, wherein the length of the window for receiving the randomaccess response is greater than 10 ms.
 4. The apparatus according toclaim 1, wherein the indication comprises an index offset in radioframes from a radio frame where the random access response is scheduled.5. The apparatus according to claim 1, wherein a same random accessradio network temporary identifier is applied in a frequency domain whenthere are more than 8 random access channel occasions in frequency. 6.The apparatus according to claim 1, wherein the transmission comprisesan Msg1 in a four-step random access procedure or an MsgA in a two-steprandom access procedure.
 7. The apparatus according to claim 1, whereinthe apparatus comprises a user equipment.
 8. An apparatus comprising: atleast one processor; and at least one memory comprising computer programcode, wherein the at least one memory and the computer program code areconfigured, with the at least one processor to cause the apparatus atleast to: configure a length of a window used by a user equipment forreceiving a random access response; receive a transmission comprising arandom access channel preamble from the user equipment; and send, inresponse to receiving the transmission comprising the random accesschannel preamble, to the user equipment, downlink control informationfor scheduling the random access response associated with thetransmission, wherein the downlink control information comprises anindication which indicates a random access channel occasion within aspan of one or a plurality of radio frames to which the random accessresponse applies, wherein the indication in the downlink controlinformation is determinable by the user equipment to decode for based atleast on a length of a window for receiving the random access response,and wherein the indication comprises a plurality of least significantbits of a system frame number corresponding to the random access channeloccasion.
 9. The apparatus according to claim 8, wherein the randomaccess response is comprised in an msg2 in a four-step random accessprocedure, or comprised in an MsgB in a two-step random accessprocedure.
 10. The apparatus according to claim 8, wherein the length ofthe window used by the user equipment for receiving the random accessresponse is greater than 10 ms.
 11. The apparatus according to claim 8,wherein the indication comprises an index offset in radio frames from aradio frame where the random access response is scheduled.
 12. Theapparatus according to claim 8, wherein a same random access radionetwork temporary identifier is applied in a frequency domain when thereare more than 8 random access channel occasions in frequency.
 13. Theapparatus according to claim 8, wherein the transmission comprises anMsg1 in a four-step random access procedure or an MsgA in a two-steprandom access procedure.
 14. The apparatus according to claim 8, whereinthe apparatus comprises a network element.
 15. A method comprising:sending, from a user equipment, to a network element, a transmissioncomprising a random access channel preamble; receiving, in response tosending the transmission comprising the random access preamble, at theuser equipment, from the network element, downlink control informationfor scheduling a random access response associated with thetransmission; and determining, based at least on a length of a windowfor receiving the random access response, to decode for an indication inthe downlink control information, wherein the indication indicates arandom access channel occasion within a span of one or a plurality ofradio frames to which the random access response applies, and whereinthe indication comprises a plurality of least significant bits of asystem frame number corresponding to the random access channel occasion.16. The method according to claim 15, wherein the random access responseis comprised in an msg2 in a four-step random access procedure, orcomprised in an MsgB in a two-step random access procedure.
 17. Themethod according to claim 15, wherein the length of the window forreceiving the random access response is greater than 10 ms.
 18. Themethod according to claim 15, wherein the indication comprises an indexoffset in radio frames from a radio frame where the random accessresponse is scheduled.
 19. The method according to claim 15, wherein asame random access radio network temporary identifier is applied in afrequency domain when there are more than 8 random access channeloccasions in frequency.
 20. The method according to claim 15, whereinthe transmission comprises an Msg1 in a four-step random accessprocedure or an MsgA in a two-step random access procedure.
 21. A methodcomprising: configuring a length of a window used by a user equipmentfor receiving a random access response; receiving a transmissioncomprising a random access channel preamble from the user equipment; andsending, in response to receiving the transmission comprising the randomaccess channel preamble, to the user equipment, downlink controlinformation for scheduling the random access response associated withthe transmission, wherein the downlink control information comprises anindication which indicates a random access channel occasion within aspan of one or a plurality of radio frames to which the random accessresponse applies, wherein the indication in the downlink controlinformation is determinable by the user equipment to decode for based atleast on a length of a window for receiving the random access response,and wherein the indication comprises a plurality of least significantbits of a system frame number corresponding to the random access channeloccasion.
 22. The method according to claim 21, wherein the randomaccess response is comprised in an msg2 in a four-step random accessprocedure, or comprised in an MsgB in a two-step random accessprocedure.
 23. The method according to claim 21, wherein the length ofthe window used by the user equipment for receiving the random accessresponse is greater than 10 ms.
 24. The method according to claim 21,wherein the indication comprises an index offset in radio frames from aradio frame where the random access response is scheduled.
 25. Themethod according to claim 21, wherein a same random access radio networktemporary identifier is applied in a frequency domain when there aremore than 8 random access channel occasions in frequency.
 26. The methodaccording to claim 21, wherein the transmission comprises an Msg1 in afour-step random access procedure or an MsgA in a two-step random accessprocedure.